Gear and profile rolling machines

ABSTRACT

A gear rolling machine, comprising a pair of opposed rotatable forming rolls supported by heads, one of which is slidable and the other of which is slidable or fixed, and a pair of hydraulic cylinders, each fixed to one of the heads, the piston rod of each cylinder being attached to the opposite head and the piston rods extending parallel to and being spaced substantially symmetrically with respect to the load axis.

United States Patent Pratt July 11, 1972 [S4] GEAR AND PROFILE ROLLING MACHINES [72] Inventor: Ledle Raymond Pratt. West Haddon, near Rugby, England [7H Assigncc; Chlrles Chillthlll Limited, Birmingham.

England [22] Filed: May 26, I970 [2H AppLNo; 40,557

[30] Foreign Application Priority Data June 2, I969 Great Britain ..27,846/69 152i US. Cl ..72/l08, 72/453 151] lnt.Cl [58] Fleld olSearch ..72/l02, 104, l08,245,453

[56] References Cited UNITED STATES PATENIS 3,533,258 10/1970 Leonard et al ..72/l08 2,559,360 7/ l 95l Kurzweil l ..29/9O 3,543,555 l2/l 970 Baumann ..72/245 Primary Examinerbowell A. Larson Attorney-Watson, Cole. Grindle & Watson ABSTRACT A gear rolling machine, comprising a pair of opposed rotatable forming rolls supported by heads, one of which is slidable and the other of which is slidable or fixed, and a pair of hydraulic cylinders, each fixed to one of the heads, the piston rod of each cylinder being attached to the opposite head and the piston rods extending parallel to and being spaced substantially symmetrically with respect to the load axis.

ZCIahmJDrawingfigure GEAR AND PROFILE ROLLING MACHINES This invention relates to gear rolling machines of the type including a pair of opposed rotating forming rolls which are given infeed to cause them to contact a centrally located workpiece. Increase of the infeed load to a sufliciently high value causes the workpiece to deform to a shape conjugate to that of the rolls.

Generally machines of this type have a fixed head and a sliding head each carrying a forming roll. lnfeed to the sliding head is effected by a hydraulic cylinder reacting against a cantilever end support. Loading reactions are generally resisted by bending of the cantilever to the machine frame. Usually the cantilever is supported by additional ties between its unsupported end and the fixed head to restrict deflections to a reasonable level. This arrangement requires heavy sections in the machine frame to maintain sufficient stiffness to ensure that deflections will be small and prevent them from affecting machine alignment as the slideways are generally mounted on the frame.

The invention provides a gear rolling machine in which the forming rolls are supported by heads, one of which is slidable and the other of which is slidable or fixed, and a pair of hydraulic cylinders, each fixed to one of the heads, the piston rod of each cylinder being attached to the opposite head and the piston rods extending parallel to and being spaced substantially symmetrically with respect to the load axis.

One embodiment of the invention illustrated in the accompanying drawing, is an end elevation of the machine, partly in section.

The drawing shows a workpiece 3 supported on a conveyor 10 and disposed between rotating forming rolls 1 and 2 driven by driving shafts 21 and 22. Pre-rotation may be imparted to the workpiece before infeed is imparted to the forming rolls to facilitate engagement of the teeth. The forming roll 1 is supported on a sliding head 1 l and the forming roll 2 is supported on a head 12 which may either be fixed or sliding.

Hydraulic cylinders 4, are mounted on the heads 11 and 12 respectively and have piston rods 6, 7 connected to the opposite heads by screws 16 and 17. When oil under pressure is supplied to the appropriate ends of the cylinders the piston rods 6, 7 are caused to retract and the heads 4, 5 to approach each other along slideways 8 and 9 on the frame of the machine. The piston rods carry adjustable dead stops 26, 27 for limiting the infeed movement imparted to the forming rolls. The piston rods 6 and 7 are symmetrically spaced about the load axis with the result that no resultant reactions will be transmitted through the machine frame or the location slideways 8 and 9. This allows the frame to be built considerably lighter than heretofore as load deflections are restricted to the piston rods parallel to the load axis and bending is obviated.

The workpieces are provided with preformed teeth, e. g. by hobbing, before they are presented before they are presented to the gear rolling machine which provides for finish forming of the teeth. to the gear rolling machine which provides for finish forming of the teeth.

What i claim as my invention and desire to secure by Letters Patent is:

1. A gear rolling machine, comprising a frame, a pair of opposed rotatable forrning rolls, a pair of heads mounted on said frame, one of said forming rolls being mounted on each said head, at least one of said heads being slidable on said frame to provide infeed of its associated forming roll with respect to a workpiece located between said forming rolls, and a pair of hydraulic cylinders, each fixed to one of said heads and each having a piston rod attached to the opposite head, said piston rods extending parallel to and being spaced substantially symmetrically with respect to the load axis between said forming rolls and said workpiece.

2. A machine as claimed in claim 1, in which the piston rods carry adjustable dead stops for limiting the infeed movement which can be imparted to the forming rolls.

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1. A gear rolling machine, comprising a frame, a pair of opposed rotatable forming rolls, a pair of heads mounted on said frame, one of said forming rolls being mounted on each said head, at least one of said heads being slidable on said frame to provide infeed of its associated forming roll with respect to a workpiece located between said forming rolls, and a pair of hydraulic cylinders, each fixed to one of said heads and each having a piston rod attached to the opposite head, said piston rods extending parallel to and being spaced substantially symmetrically with respect to the load axis between said forming rolls and said workpiece.
 2. A machine as claimed in claim 1, in which the piston rods carry adjustable dead stops for limiting the infeed movement which can be imparted to the forming rolls. 